1. Field of the Invention
This invention relates to a lactoferrin table. More particularly, this invention relates to a lactoferrin tablet having such pharmacological actions as protection of infection and immunopotentiation and, in addition, having very high hardness.
2. Description of the Related Art
Lactulose is a kind of disaccharide (4-O-.beta.-D-galactopyranosyl-.alpha.-fructose) consisting of galactose and fructose and is produced by subjecting lactose to a Lobry de Bruyn transformation. Lactulose has been known as a growth factor for bifidobacteria (Shindan to Shinyalu, volume 80, number 5, page 75, 1973) and used in a modified dry milk, dry milk for the weaning period, etc. In addition, lactulose has been known to have an action of reducing the symptoms of hepatic encephalopathy and hepatic coma, and has been used for the therapy already (Seishirl Igaku, volume 15, number 10, page 1101, 1973).
However, it has not been known yet that lactulose is effective as an excipient for increasing the hardness of tablets.
On the other hand, lactoferrin is a non-toxic and natural iron-binding protein contained in tear, saliva, peripheral blood, milk, etc and has been known to have an antimicrobial action to toxic microorganisms such as Escherichia coli, Candida, Closttidium, etc. (Journal of Pediatrics, volume 94, page 1, 1979). It has been also reported that lactoferrin is effective for staying useful microorganisms such as bifidobacteria and lactobacillus to intestine of human being and animals (Japanese Patent No. 2,532,911).
Up to now, lactoferrin has been compounded in modified dry milk for babies and small children, etc. and, with regard to one of the means for adults to take the necessary dose easily, and conveniantly, an art concerning lactoferrin-containing powder (Japanese Patent No. 2,532,911) and granules (JP 8-253423 A) has been known. Further, as one of the methods for making the oral administration of powdery lactoferrin easy, it has been known to make it into tablets (Drug Topics, Sep. 9, 1996), and tablets containing Lactoferrin have been put into the market since October 1996.
Incidentally, a tablet is usually easily taken as one dosing unit, can be easily administered and is relatively easily produced and, because of such reasons, tablets are utilized in many pharmaceuticals, health foods, etc. After being produced. tablets are packed and transported and, since the tablets receive considerable force from outside such as shaking and impact during such steps, they are to be made for having an appropriate mechanical strength so that the tablets are not disintegrated and keep their commercial value.
When a tablet containing lactoferrin is taken by chewing, broken pieces of the tablet adhere to the inner wall of the oral cavity such as teeth upon chewing resulting in a decrease in a favorable taste whereby the taste significantly decreases unless the tablet has hardness of some extent.
Hardness of tablet is measured by disintegration using a conventional method by applying a static pressure to a horizontal direction and a load to a vertical direction and hardness of each direction is expressed in a unit of kg. The vertical direction is a direction in which a pestle compresses the material upon tableting, while the horizontal direction is a direction in a right angle to the horizontal direction.
In the commercially available lactoferrin-containing tablets, their hardness in the horizontal direction is about 3.1 kg in average while that in the vertical direction is about 1.6 kg in average. Thus, the hardness is extremely low and this is a big problem in terms of the rigidity of the tablet.
The inventors of this application have conducted many attempts for the manufacture of tablets according to conventional methods by adding known excipients such as a starch (e.g. corn starch) and a saccharide (e.g., lactose and sucrose) to lactoferrin but obtained tablets having only low hardness.
The inventors further tried tableting by a conventional method using granules which were prepared by granulating a mixture of all of or a part of materials for the tablets. In that case, hardness increased and improvement in the tablet hardness was noted as compared with the already-mentioned case where the powdery materials are directly tableted although the result was still unsatisfactory as stable tablets which are durable for transportation as a commercial product.
As one of the means for increasing the hardness of tablets, an increase in the tableting pressure was known (lyakuhin Kaihatsu Kiso Koza--Seizai Kogaku [Elementary Textbook on Development of Pharmaceuticals--Tablet Manufacturing Technology], page 156, published by Chijin Shokan, 1971). However, in making a lactoferrin-containing composition into tablets, an excessive tableting pressure is not favorable because it causes a capping (detachment of the upper surface of tablets), lamination (detachment in layers), etc. upon tableting and there is a problem of causing a decrease in the remaining number of viable cells in making a composition containing viable microbial powder of lactobacillus into tablets.